Rotary slide rule



ROTARY SLIDE RULE Filed Jan. 23, 1942 6 Sheets-Sheet 1 INVENTOR. BERNARD SASSEN.

ATTORNEY.

ROTARY SLIDE RULE Filed Jan. v23, 1942 e sheets-Sheet 2 INVENTOR. BERNARD SASSEN ATTQRNEY.

Sept. 19, 1944. B. sAssEN ROTARY SLIDE RULE e Sheets-sheet s Filed Jan. 23, 1942 INVENTOR Illl BERNARD SAS5EN.

ATTO R NEY.

Sept. 19, 1944. B. sAssENA ROTARY SLIDE RULE 6 Sheets-Sheet 4 Filed Jan. l23, 1942 ll lll' INVENTOR. BERNARD SASSEN.

ATTORNEY.

Sept. 19,' 1944. B, SASSEN 2,358,478

ROTARY SLIDE RULE Filed Jan. 23, 1942 6 Sheets-Sheet 5 I2-ig. ,Q l0 1 a L; l

lll

)7.4 IOS INVENTOR.

BERNARD SASSEN.

BY gg M ATTORNEY.

Sept. 19, 1944. B. sAssEN 2,358,478

' ROTARY SLIDE RULE I Filed.Jan. 23, 1942 6 Sheets-Sheet 6 n N. W 5 w A M m m E a M 9 4 s :y S .f ,vll f r, m@ L Patented Sept. 19, 1944 UNITED sTATEs PATENT OFFICE ROTARY sLmE RULE Bernard saen, springfield, vt. Application Januaryy 23, 1942, serial No. 427,848

(ci ass-79.5)

11 Claims.

This invention relates to a rotary slide rule for quickly and accurately determining the multiplication and/or division of a plurality of various figures through the process of rotating a hand knob and operating a trip lever.

In the usual slide rule, it is often necessary to transfer figures from one side of the rule to the other side to complete a given calculation, together with a movement of the cursor along the scale when more than two values are involved in the calculation, with the resultant difficulty of accurately setting the scales and cursor to 'obtain the correct result, while in the present invention, the cursor is on a fixed window of a housing in which the scales revolve by means of a rotary movement of a hand knob under tension, permitting a quick and accurate setting of the scales. In all other slide rules whether straight-line or rotary, in order to multiply or divide by a series of values it is necessary to position one of the scales to unity and then to position either the cursor or one o1' the scales to the desired factor i or divisor. In my improved device the positioning to unity is accomplished automatically merely by pressing a release lever.

The repetition of two simple operations for each factor or divisor involved in the calculation is all that is necessary to complete any calculation within the scope of the scales, namely; rotating a hand knob and depressing a trip lever.

Furthermore, the invention'contemplates the use of microscopic scales in association with microscopic legends inscribed on a mask having an opening which permits a minute portion of the scales to be visible adjacent to the hair-line. Such scales permit the use of a number of digits opposite the calibrations, thereby reducing the danger of misreading the scales and yet confining the device to a small and portable instrument. The advantages inherent in the use of microscopic legends and scales are to increase the effective or apparent length of the scale without increasing the actual physical magnitude, and the ability of having a large number of scales in the instrument confined within a narrow band, thus reducing the field and permitting the use of a small microscope with a great magnication.

In previous slide rules when multiplying and/or dividing more than two numbers, there are two line-setting operations needed for each subsequent number: (1) the bringing of unity on the sliding ysca'le to the cursor, and (2) the bringing of the cursor to the succeeding factor or divisor. Since in making such calculations, it is this fine-setting that consumes the greatest part of the time in completing calculations, the use of almost instantaneous and automatic means to eiiect one of these two tine-setting operations, namely; the bringing of unity on the sliding scale to the cursor, the total time for the entire calculation may be virtually halved when several factors or divisors are involved. Furthermore, since the accuracy of the nal answer depends to a large extent on the accuracy with which each positioning operation is performed, this automatic and therefore' completely accurate means for performing one-half of the total number of settings may be said to halve the possibility of total error.

The object of the invention is to provide a small device capable of great accuracy and having a number of various mathematical scales rotatable into registry with a fixed hair-line, wherewith a speedy result can be obtained in either multiplication and/or division, through the simple procedure of rotating a hand knob and operating a release lever.

A further object of my invention is to provide a pair 0I rotatable members having a correlated actuation through the medium of a hand knob in opposition to retra'cting means imposed on one of the members, means for disengaging said members from each other, and thus permitting' said retracting means to return the released member to unit position while the other member is retained in set position.

A further object is to provide a series of microscopic scales on one of the rotatable members and a microscopic answer scale on the other rotatable member in association with a iixed hair-line and an adjustable magnifying lens through which the scales can be read.

A further object is to completely encase the microscopic scales, which because of their minuteness would otherwise be vulnerable to damage. n

A further object is to frame only a minute portion of the slide rule to expedite reading of the scales reducing the ileld of the microscope, thereby permitting greater magnification.

A further object of the invention is to provide a device whereby all calculations are made through two basic operations, each of which is entirely controlled by leither the left or right hand, with one hand used entirely for the purpose of setting to unity, and the other hand to setting the next factor, thereby reducing the danger of confusion whichA `so often results in the use o1' the ordinary slide rule.

A further object is' to provide an opaque shield in association the hairnline having suitable legends thereon for informative reading of the scales, said shield having an opening to permit window, partly broken away, showing the hairline, mask and scales as viewed through the window.

Fig. 5 is a vertical section ofthe same, taken in the plane of the line .il-5 ot Fig. 3.

Fig. 6 is a detail sectional view, partly broken away, taken in the plane of the line d-- of Fig. 2.

Fig, 7 is a vertical sectional View, taken in the plane of the line l-i of Fig. 3.

iii

ifi

Fig. 8 is a side view of a modied form oi' my invention, partly broken away and partly in section with the parts thus shown in section, taken in the plane of the line 0i Fig. 9.

Fig. 9 is an axial section of the same, taken in the plane of the line .ii-9 of Fig. i0, and;

Fig, 10 is a vertical section of the same, taken in the plane of the irregular line ld--iil of Fig. 9. The various scales of all slide rules start with the numeral i and reference to unit position or unity as herein set forth refers to the position of the scales whereby the numeral i on the scale will coincide with the hairline.

My improved device comprises a casingl II having a cover I 2 attached thereto as by screws I3. A rotatable member It has extending hubs it and I. The hub Iii is journalled in the casing and has a hand knob Il secured thereto as by screws i8. A spring washer i9 isinterposed between the hub I6 and the h'and knob il creating a pressure against a friction ring secured to the outer face of the casing. A second friction ring 2| is secured to the inner face of the casing and creates a frictional resistance between the casing and the rotatable member |55. A scalecarrying ring 22 is secured to the rotatable member I4 as by screws 23.

A disc 3@ is secured to the hub I5 as by screws 3| and has extending hubs 32 and 33. 'I'he hub 32 extends into the bore 3d of the hub I5. A trip pin 35 is movable endwise in a. bore 3E in the hubs 32 and 33, and is provided with an enlarged head 31 slidable in the bore 36. A pin 38 is carried by and extends transversely through the enlarged end of the trip pin and through an enlarged transverse aperture 39 in the hub I5. The ends of the pin 38 are secured in a collar 40 slidable on the outer periphery of the hub I5.

A rotatable member has a hub 46 rotatable about the hub I5 being positioned between the Adisc 30 and the collar 40. A friction ring 41 is secured to the member 45, for driving the member 45 through frictional contact with the disc 30, being urged into contact by a coil sprmg 48 positioned in the bore 34 between the head of the pin 35 and the hand knob I1. The disc 80 is rotated by the hand knob in unison with the member I4.

The rim 49 of the member 45 has a scale car.- ryin'g ring 50 secured thereto and a formed spiral ods groove el in the outer face, with the ends 52 and titi of the spiral groove overlapping.

Journalled within the cover i2 is a disc bfi having a hub 55 in which the hub 33 of the disc revolves. The disc 5d is suitably secured to the cover as by screws titi. iA slot 5l is formed in the disc @l for maintaining a key Et. The key 5o is slidable radially in the slot and has an extending lug 59 which rides in the spiral groove 5i, thus limiting the rotatable member i5 to slightly in excess of one complete revolution.

interposed between the rim it? of the rotatable member l5 and the hub titi is a spiral spring having one end @i engaged in an aperture 62 in the hub 55 and the other end t3 engaged in an aperture @il in the rim, for returning the member lb to unity position upon depression of the coil spring f3@ which is designed to create a frictional driving force greater than that of the spiral spring.

A scale t5 having a plurality of rows of figures thereon for multiplication and/ or division, indicated at 6b and 6l, is received in a groove de in the ring 69. An answer scale l0 having properly arranged iigures thereon as indicated at ll is received in a peripheral groove l2 in the ring 22. Both of these scales completely surround the respective'rotatable-members and are held in place by any suitable means such as crimping of the edges of the grooves in which they are positioned.

The face of the cover I2 is provided with a pair of ribs i3 between which a trip lever 'Iii is pivoted on a pin lo xed in the ribs. This lever is arranged to actuate the trip pin 35.

Mounted on the top of the casing and extending through an aperture therein, is a transparent member 8i having a face 82 in close proximity to the scales 65 and 10. A hair-line 83 is inscribed on the face 82 and extends tranversely across the scales. An opaque mask 84 is secured to the lower face 82. The center portion of the mask is cut out as at 85 to permit a clear view of the scales adjacent to the hair-line. There are suitable legends, as indicated at 88, on the mask for .informative reading of the scales. The scales are of microscopic size and are made visible by means of an enlarging lens suitably secured in an adjustable arm 9|. This arm is shaped to fit the casing upon retraction of the lens to provide a compact unit which can be carried in the pocket of the user. 'Ihe arm 9| is supported between a pair of ribs 92 and 93 on the casing. Screws 94 are molded in the casing and extend through elongated slots 95 in the arm. Nuts 96 are provided to clamp the arm to the casing in any desired position, to suit the .focal requirements of the user.

Figs. 8 to 10 show a modified form of the invention, wherein free-wheeling clutches are used -to engage the rotary members andy to maintain the two scales in unit rotation, in place of the friction rings used in the preferred form of the invention. A casing IOI has a, central bore |02 in which the hub of a rotary member |03 is jour- 5 nailed. The rotatable member |03 has a central bore |04 through which the shank |05 of a hand knob |06 extends. The hand knob is secured to the hub of the rotatable member |03 as by screws |01. A cap |08 having a forward tapered face |09 is slidable on the shank |05 being retained in an outward position by means of a. spring I|0 interposed within the bore III of the shank between a pin I|2 and a threaded plug |I3. A plurality of pins I4 are fixed to the rotatable mem- 75, ber |03 and carry clutching arms I I5 arranged to engage the inner face of a rotatable member III having balls I I1 interposed between the arms and the tapered face in apertures IIB in the extended hub III oi' the rotatable member |03. Springs normally urge the arms I I5 into contact with the rotatable member IIB. Similar arms |I5' are pivoted about pins IZI extending from the casing and engage the rotatable member |03 being held in engagement by means of springs |22, but are not releasable. A cover |23 is Secured to the casing and has an inwardly extending hub |24 within which the hub |25 of the rotatable member II5 rotates. A spiral spring |23 has one of its ends |21 engaged in an aperture |23 in the hub |24 and its other end |29 engaged in an aperture in the rim |3I of the rotatable member IIS. The rim I3I is provided with a spiral groove |32 which is similar to the spiral groove 5I of the preferred form of the invention for limiting rotation of the rotatable member I I 5 to one complete revolution by means oi' the key |33 slidable in the slot |34 in a plate secured to the cover |23 with the lug |35 of the key |33 riding in the spiral groove |32. The respective rotatable members IIS and |03 carry scales |31 and |33 similar to the scales of the preferred form. The lens mounting, hair-line, mask and trip arm are similar tothat shown in the.

preferred form of the invention and given similar reference numerals.

In the operation of the preferred form of my invention, the casing can be either placed on a suitable support or held in the left hand of the user with the right hand engaging the hand knob l1. Assuming it is desired to multiply 2 3 4, the hand knob is rotated in a clock-wise direction until the number 2 on the answer scale registers with the hair-line. The trip lever 14 is then depressed by the lingers of the right hand causing the collar 40 to move inwardly releasing the frictional contact between the disc 30 and the rotatable member which permits the spiral spring to rotate the member 45 in a counterclockwise direction to bring the multiplication scale back to unity, during which time the answer scale is held against rotation by the friction rings 20 and 2|. 'Ihe trip lever is then released causing the friction ring 41 to again engage the disc 30 with the rotatable member 45. "I'he hand knob is turned in a clock-wise direction until the number 3 appears on the multiplication scale in registry with the hair-line.

At this point the number 6 will be in registry with the cursor on the answer scale. 'I'he trip lever is again depressed permitting the multiplication scale to return to unity after which it is released and the hand knob rotated until the number 4 appears on the multiplication scale in registration with the cursor. The number now appearing on the answer scale in registration with the cursor will be 24, or the product of 2 3 4. In a like manner any other numbers can be multiplied and/or divided through the same procedure as just described, including square root, cube root, sines, cosines, tangents, and cotangents. When multiplying or dividing an equation not involving a whole number the answer scale must be set to unity before starting the calculation.

In the preferred form the coil spring 48 imposes sumcient tension on the member 45 through the friction ring 41 to maintain'the member 45 in any turned position while being opposed by the spiral spring. The 'spring washer I9 maintains sumcient tension on the friction ring 20 to hold the hand knob and the rotatable member I4 in I4 position during any reverse movement of the rotatable member 4I.

The operation of the modified form of the invention is similar in its procedure with the exception that the members cannot be rotated in a reverse direction due to the type of clutch used to engage the members. The answer scale must always be brought around clock-wise to its unit position at the beginning of any series'of calculations. 'I'he multiplication and division scale is releasable from the clutch arms by means of the trip lever engaging the cap |03 and causing the faces |00 to push the balls I I1 outwardly for disengaging the ends of the arms with the inner face of the rotatable member I |6 when itis desired to bring the member I I6 back to unit position under the impetus of the spring |28.

It will thus be noted that the same procedure is followed in the modied form as in the preferred form of this invention, and it will be noted that the scale used for division is in the opposite directionto that of the multiplication scale, and that the readings for sines, cosines. tangents, and cotangents are set forth by degrees, which eliminates the necessity of iinding the numerical values thereof. I

In the modified form the arms I I5 lock the rotatable member I 03 against reverse movement while the arms |I5 are disengaged from the rotatable member II6 through the trip arrangement to permit the spiral spring to return the member I I6 to unit position.

From the foregoing, it will be seen that I have devised a comrpalct, efllcient slide rule, reducing the number of steps necessary to complete any given calculations in comparison to slide rules generally in use, and by means of the magnification of the scales great accuracy can be obtained from the plurality of scales incorporated on the single rotatable member. While I have shown and described various mathematical tables for the use of mechanical engineers and the like, it will be readily understood that comparable scales for other purposes might readily be substituted for the type of scale shown. It will be readily seen that it requires no special instructions to operate the device but merely the turning of the hand knob to bring the proper number or other indicated ligure on either the multiplication or division scale in registration with the hair line, depressing the trip lever for. automatically returning the multiplication and division scale to unit |position and repeating this same procedure to complete the calculation, and reading the answer on the answer scale is all that is required to complete any calculation capable of being read on any of the combined scales.

Having thus fully described my invention, what I claim as new and desire to secure by Letters Patent, is:

1. In a, rotary slide rule, a casing, a first disc in said casing, a hand knob outside said casing fastened to the disc and adapted to rotate it, a window in the casing bearing a. mark, a scale carried by said disc in alignment with the window, a second disc in said casing, a scale carried by the second disc 'in alignment with the window, a spring-pressed coupling normally interconnecting the two discs, a motor spring in the casing for the second disc, and a pin projecting to the outside of the casing for actuating the coupling.

2. The rotary slide rule according to claim l,

and a stop for the second disc towards which the motor spring tends to rotate it.

3. The rotary slide rule according to claim 1, and in which the second disc is provided with a groove having overlapping ends, and a stop xed to the casing and projecting in the groove.

4. The rota-ry slide rule according to claim i, and in which means are provided to rprevent the rotation of the first disc by the motor spring when the two discs are coupled.

5. The rotary slide rule according to claim 1, and in which means are provided to prevent the rotation of the second disc by the motor spring while the two discs are coupled.

p 6. In a rotary slide rule, a casing, a rst disc in said casing, a hand knob outside of said casing fastened to the disc and adapted to rotate it, a coupling between said casing and disc, a window in the casing bearing a mark, a scale carried by said disc in alignment with the window, a second disc in said casing, a scale car ried by the second disc in alignment with the window, a spring-pressed coupling normally operatively linking th'e two discs, means for limiting the rotation of the second disc with respect to the casing, a motor spring in the casing for the second disc, and a pin projecting to the outside of the casing for actuating the coupling to uncouple the two discs.

7. The rotary slide rule according to claim 6 and in which the coupling between the first disc and the easing is a, friction coupling which overcomes the torque of the motor spring when the two discs are coupled.

8. 'I'he rotary slide ruie according to claim 6, and in which a friction coupling is provided between the second and first discs which overcomes the torque of the motor spring while the two discs are linked by the spring-pressed coupling.

9. 'I'he rotary slide rule according to claim 6,

-and in which the second disc is provided with a spiral groove having overlapping ends, said stop -projecting into said groove, the thickness of the stop and the extent of overlap being such as to allow a complete revolution of the second disc with respect to the casing.

10. In a rotary slide rule, a casing, a first disc in said casing, a hub projecting from the disc to the outside of said casing, a hand knob fastened to the hub, a spring-pressed friction ring between the end' wall and the knob, a friction ring between the end wall and the disc, a window in the side wall having an apertured mask bearing suitable legends, a hair line on said window, a scale attached to said disc in alignment with the aperture and certain legend of the window mask, a, second disc in said casing fastened tothe first disc, ,a third disc rotatablymounted between the Yfirst, and second discs, a plurality of scales carried by the third disc in alignment with certain other legends on the mask and the aperture in the window, a friction ring between the third and the second discs, a stop having a. limited radial movement with respect to said casing and limiting, in turn, the rotation of the second disc to one complete revolution. a motor spring in the casing having one end fastened to the third disc and the other end to the casing, said friction rings overcoming the torque exerted by the motor spring on the discs while they are coupled, and a spring-pressed coupling including a pin projecting to the outside of the casing normally coupling the first to the third disc and adapted when axially displaced to uncouple said discs and allow the third disc to be rotated by the motor spring.

1l. In a rotary slide rule, a. casing havingtwo parallel end walls and a polygonal side wall, a rst disc in said c adjacent one end wall and having an enlargedl rim, a hub projecting from the disc through said one end wall to the outside and a hub projecting to the inside of said casing, a. hand knob fastened to the outside hub adjacent saidone end wall, a spring-pressed friction ring between the outer face of the end wali and the knob, a friction ring between the inner face of said end wall and the disc, a window in the side wall h aving an apertured mask bearing suitablelegends, a hair line on said window, an answer scale attached to the rim of said disc in alignment with the aperture and certain legend of the window mask, a second disc in said casing 4fastened to the inwardly projecting hub of the disc and engaging the second disc near the periphery thereof, a fourth disc in said casing fastened to the other end wall and having a hub surrounding the hub of the second disc, the fourth disc having a. slot in which a key is slidably mounted, a lug projecting from said key into the groove in th'e edge of said rim, said groove forming a complete spiral with its ends overlaprping, a spiral spring within a chamber formed by the third and fourth discs and the rim of the third disc to which one end of said spring is fastened, the other end being fastened to the hub of the fourth disc, the friction exerted by the friction rings on the first and third discs being sufllcient to overcome the torque exerted by the spiral spring on the discs and thus prevent the rotation4 thereof when said discs are coupled, a pin projecting through the hubs of the second, third and fourth discs and the other end wall to the outside of the casing, a head for said pin, a coiled spring within the hub of the rst disc, normally pressing the pin head into frictional engage-- ment with th'e third disc, and a spring-pressed lever mounted on the outside of-the other end wall and adapted axially to displace the pin against the tension of the coiled spring to push tliise pin head out of engagement with the third BERNARD SASSEN. 

